Electric fluid pump

ABSTRACT

An electric machine is presented. The electric machine includes a hollow rotor; and a stator disposed within the hollow rotor, the stator defining a flow channel. The hollow rotor includes a first end portion defining a fluid inlet, a second end portion defining a fluid outlet; the fluid inlet, the fluid outlet, and the flow channel of the stator being configured to allow passage of a fluid from the fluid inlet to the fluid outlet via the flow channel; and wherein the hollow rotor is characterized by a largest cross-sectional area of hollow rotor, and wherein the flow channel is characterized by a smallest cross-sectional area of the flow channel, wherein the smallest cross-sectional area of the flow channel is at least about 25% of the largest cross-sectional area of the hollow rotor. An electric fluid pump and a power generation system are also presented.

BACKGROUND

One or more aspects of the invention described herein were developedunder Cooperative Agreement DE-EE0002752 for the U.S. Department ofEnergy entitled “High-Temperature-High-Volume Lifting for EnhancedGeothermal Systems.” As such, the government has certain rights in thisinvention.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present invention provides an electric machineconfiguration. In a particular aspect, the present invention provides anelectric motor configuration, which is particularly useful for wellfluids lifting systems.

Well fluid lifting systems, such as, for example, electrical submersiblepump (ESP) systems are used in a wide variety of environments, includingwellbore applications for pumping production fluids, such as water orpetroleum. The submersible pump system includes, among other components,an induction motor used to power a pump, lifting the production fluidsto the surface. A conventional motor employed in a well fluid liftingsystem includes a stator and a rotor located inside the stator, suchthat the fluid to be pumped flows outside the rotor and the stator.However, a major challenge with the conventional well fluid liftingsystems is to provide electric machine configurations that can withstandthe extreme pressure and temperature of thermal energy recovery wellswhile providing the maximum power for pumping the fluid.

Thus, there is a need for improved electric machine configurations, suchas, for example, electric motor configurations with high power ratingsthat provide for improved rate of production and are capable ofwithstanding the extreme temperature and pressure conditions.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one aspect of the present invention, an electricmachine is presented. The electric machine includes a hollow rotor; anda stator disposed within the hollow rotor, the stator defining a flowchannel. The hollow rotor includes a first end portion defining a fluidinlet, a second end portion defining a fluid outlet; the fluid inlet,the fluid outlet, and the flow channel of the stator being configured toallow passage of a fluid from the fluid inlet to the fluid outlet viathe flow channel; and wherein the hollow rotor is characterized by alargest cross-sectional area of the hollow rotor, and wherein the flowchannel is characterized by a smallest cross-sectional area of the flowchannel, wherein the smallest cross-sectional area of the flow channelis at least about 25% of the largest cross-sectional area of the hollowrotor.

In accordance with another aspect of the present invention, an electricfluid pump is presented. The electric fluid pump includes an electricmotor including a hollow rotor; and a stator disposed within the hollowrotor, the stator defining a flow channel. The hollow rotor includes afirst end portion defining a fluid inlet, a second end portion defininga fluid outlet; the fluid inlet, the fluid outlet, and the flow channelof the stator being configured to allow passage of a fluid from thefluid inlet to the fluid outlet via the flow channel; and wherein thehollow rotor is characterized by a largest cross-sectional area of thehollow rotor, and wherein the flow channel is characterized by asmallest cross-sectional area of the flow channel, wherein the smallestcross-sectional area of the flow channel is at least about 25% of thelargest cross-sectional area of the hollow rotor. The electric fluidpump further includes a transition coupling configured to join thehollow rotor to a drive shaft of a pumping device to be powered by theelectric motor; and one or more intake ports defined by the transitioncoupling, the first end portion, or both the transition coupling and thefirst end portion, said intake ports being in fluid communication withthe fluid inlet and the flow channel of the stator. The electric fluidpump furthermore includes a pumping device including one or moreimpellers fixed to a drive shaft powered by the electric motor.

In accordance with yet another aspect of the present invention, anelectric power generation device is presented. The electric powergeneration device includes a generator including a magnetic hollowrotor; and a stator disposed within the hollow rotor, the statordefining a flow channel. The magnetic hollow rotor includes a first endportion defining a fluid inlet, a second end portion defining a fluidoutlet; the fluid inlet, the fluid outlet, and the flow channel of thestator being configured to allow passage of a fluid from the fluid inletto the fluid outlet via the flow channel; and wherein the magnetichollow rotor is characterized by a largest cross-sectional area of thehollow rotor, and wherein the flow channel is characterized by asmallest cross-sectional area of the flow channel, wherein the smallestcross-sectional area of the flow channel is at least about 25% of thelargest cross-sectional area of the magnetic hollow rotor. The electricpower generation device further includes a transition couplingconfigured to join the magnetic hollow rotor to a drive shaft of aturbine device configured to drive the hollow magnetic rotor; and one ormore outlet ports defined by the transition coupling, the second endportion, or both the transition coupling and the second end portion;said outlet ports being in fluid communication with the flow channel ofthe stator. In some embodiments, the electric power generation devicefurther includes a turbine device including one or more impellers fixedto the drive shaft. In some further embodiments, the turbine deviceincludes a turbine device housing defining one or more fluid inlets.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 illustrates a schematic of an electric machine in accordance withone or more embodiments of the present invention;

FIG. 2 illustrates a schematic of an electric machine in accordance withone or more embodiments of the present invention;

FIG. 3 illustrates a schematic of an electric motor in accordance withone or more embodiments of the present invention;

FIG. 4 illustrates a schematic of an electric motor in accordance withone or more embodiments of the present invention;

FIG. 5 illustrates a schematic of an electric motor in accordance withone or more embodiments of the present invention;

FIG. 6 illustrates a schematic of a transition coupling in accordancewith one or more embodiments of the present invention;

FIG. 7 illustrates a schematic of an electric motor in accordance withone or more embodiments of the present invention

FIG. 8 illustrates a schematic of a transition coupling in accordancewith one or more embodiments of the present invention;

FIG. 9 illustrates a schematic of an electric machine in accordance withone or more embodiments of the present invention;

FIG. 10 illustrates a schematic of an electric machine in accordancewith one or more embodiments of the present invention;

FIG. 11 illustrates a schematic of an electric fluid pump in accordancewith one or more embodiments of the present invention;

FIG. 12 illustrates a schematic of a geothermal energy extraction systemin accordance with one or more embodiments of the present invention; and

FIG. 13 illustrates a schematic of a power generation system inaccordance with one or more embodiments of the present invention.

DETAILED DESCRIPTION

As discussed in detail below, some of the embodiments of the inventionrelate to electric machine configurations. In some further embodiments,the present invention provides electric motor configurations and pumpingsystems including the electric motor configurations, which areparticularly useful for well fluids lifting systems, such as, forexample ESP systems.

The electric machine configurations in accordance with some embodimentsof the invention advantageously provide for increased power density(power per unit length) of a machine compared to conventional machines.Further, in embodiments wherein the electric motor functions as acomponent of an electric submersible pump (ESP), the rate of productionfrom a single well may be increased using the motor configurationsdescribed herein. Furthermore, the motor configurations in accordancewith some embodiments of the invention may advantageously provide forimproved thermal management.

In the following specification and the claims, the singular forms “a”,“an” and “the” include plural referents unless the context clearlydictates otherwise. As used herein, the term “or” is not meant to beexclusive and refers to at least one of the referenced components beingpresent and includes instances in which a combination of the referencedcomponents may be present, unless the context clearly dictatesotherwise.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about”, and “substantially” is not to be limited tothe precise value specified. In some instances, the approximatinglanguage may correspond to the precision of an instrument for measuringthe value. Here and throughout the specification and claims, rangelimitations may be combined and/or interchanged, such ranges areidentified and include all the sub-ranges contained therein unlesscontext or language indicates otherwise.

In some embodiments, an electric machine is presented. The term“electric machine” as used herein refers to electric motors andgenerators. Referring to FIG. 1, in some embodiments, the electricmachine 100 includes a hollow rotor 20 and a stator 30 disposed withinthe hollow rotor 20. The stator 30 defines a flow channel 35 asindicated in FIG. 1. As further indicated in FIG. 1, the hollow rotor 20includes a first end portion 24 defining a fluid inlet 27 and a secondend portion 26 defining a fluid outlet 29. In some embodiments, thefluid inlet 27, the fluid outlet 29, and the flow channel 35 of thestator 30 are configured to allow passage of a fluid (indicated bydirection arrows 70) from the fluid inlet 27 to the fluid outlet 29 viathe flow channel 35, as illustrated in FIG. 1. As will be appreciated byone of ordinary skill in the art, the electric machine configuration 100of FIG. 1 may represent an electric motor configuration or a generatorconfiguration.

In some embodiments, as described in detail later, an electric motor ispresented, the electric motor includes the configuration as describedherein above. The motor configurations as described herein may also bereferred to as “outside rotor motor” as the rotor is disposed outsidethe stator as compared to conventional motor configurations having arotor disposed inside the stator. The fluid that passes through the flowchannel 35 may also be referred to as a “working fluid”, and the terms“fluid” and “working fluid” are used herein interchangeably.

In some embodiments, the hollow rotor 20 is characterized by a largestcross-sectional area of hollow rotor 20, as indicated by 22 in FIG. 1.The term “largest cross-sectional area as used herein refers to thecross-section area occupied by the hollow rotor, that is, thecross-section area defined by the outside dimension of the hollow rotor.In some embodiments, the flow channel 35 is characterized by a smallestcross-sectional area of the flow channel, as indicated by 32 in FIG. 1.In some embodiments, the smallest cross-sectional area 32 of the flowchannel 35 is at least about 25% of the largest cross-sectional area 22of the hollow rotor 20. In some embodiments, the smallestcross-sectional area 32 of the flow channel 35 is from about 25% toabout 75% of the largest cross-sectional area 22 of the hollow rotor 20.In some embodiments, the smallest cross-sectional area 32 of the flowchannel 35 is from about 30% to about 55% of the largest cross-sectionalarea 22 of the hollow rotor 20.

Without being bound by any theory, it is believed that the electricmachine configurations in accordance with some embodiments of theinvention advantageously provides for increased power density of amachine (such as, for example, an electric motor) compared toconventional machines. The increased power density may result from thearrangement of the rotor outside the stator, and the purposefulplacement of the magnetic elements of the electric machine at thelargest diameter possible within the allowed space. Further, inembodiments wherein the electric motor functions as a component of anelectric submersible pump (ESP), the rate of production from a singlewell may be increased using the motor configurations described herein.

In some embodiments, as indicated in FIG. 1, the stator 30 is disposedcoaxially within the hollow rotor 20. The term “coaxial” as used hereinmeans that a geometrical axis of the stator 30 coincides with arotational axis of the hollow rotor 20. In some other embodiments, thegeometrical axis of the stator 30 may be longitudinally or laterallydisplaced with respect to the rotational axis of the hollow rotor 20. Inparticular embodiments, the stator 30 is disposed coaxially within thehollow rotor 20.

In some embodiments, the electric machine 100 is further disposed withina housing such that the hollow rotor is configured to rotate within thehousing. Referring now to FIG. 2, the figure illustrates an electricmachine 100 in accordance with some embodiments of the invention. Theelectric machine 100 includes a housing 10 and a hollow rotor 20disposed within the housing 10. In some embodiments, the hollow rotor 20may be supported within the housing 10 using a plurality of bearings 12,such as, for example, radial bearings. As indicated in FIG. 2, theelectric machine 100 further includes a stator 30 disposed within thehollow rotor 20. The stator 30 defines a flow channel 35 as indicated inFIG. 2.

As further indicated in FIG. 2, the hollow rotor 20 includes a first endportion 24 defining a fluid inlet 27 and a second end portion 26defining a fluid outlet 29. In some embodiments, the fluid inlet 27, thefluid outlet 29, and the flow channel 35 of the stator 30 are configuredto allow passage of a fluid (indicated by direction arrows 70) from thefluid inlet 27 to the fluid outlet 29 via the flow channel 35, asillustrated in FIG. 2. In some embodiments, a gap 13 between the housing10 and an outer surface of the hollow rotor 20 is configured to allowpassage of a portion of the fluid, as indicated by direction arrows 72in FIG. 2

In some embodiments, the electric machine further includes a transitioncoupling configured to join the hollow rotor to a drive shaft of adevice, such as, for example, a pump or a turbine device. In someembodiments, wherein the electric machine is an electric motor, thetransition coupling is configured to join the hollow rotor to a driveshaft of a device to be powered by the motor. In some embodiments, theelectric machine further includes one or more intake ports defined bythe transition coupling, the first end portion, or both the transitioncoupling and the first end portion; said intake ports being in fluidcommunication with the fluid inlet and the flow channel of the stator.

Referring now to FIG. 3, the figure illustrates an electric motor 100 inaccordance with one embodiment of the present invention, the motor 100includes a transition coupling 40 configured to join the hollow rotor 20to a drive shaft 50 of a device (not shown) to be powered by the motor100. In the embodiment shown, intake ports 60 allow a fluid to pass intothe flow channel 35 via the fluid inlet 27 as suggested by flowdirection arrows 70. In some embodiments, the intake ports 60 arecharacterized by one or more cross sectional areas, and a sum of thesecross sectional areas of the intake ports is substantially equal to, orlarger than, the smallest cross-sectional area of the flow channel 35.

In some embodiments, the transition coupling 40 is integral to the driveshaft 50 of the device to be powered by the motor 100 and couples to thehollow rotor 20. Referring now to FIG. 4, the figure illustrates anelectric motor 100 in accordance with one embodiment of the presentinvention. In the embodiment shown, the motor 100 is coupled to driveshaft 50 of a pump (not shown) configured to pump a fluid into andthrough the flow channel 35. In the embodiment shown, transitioncoupling 40 is shown as integral to the drive shaft 50. In thisembodiment, the transition coupling defines intake ports 60, and thefirst end portion 24 of the hollow rotor 20 lacks intake ports. Itshould be noted that transition coupling 40, in this or any otherembodiment, is not considered when determining the smallestcross-sectional area of the flow channel.

In some other embodiments, the transition coupling 40 is integral to thehollow rotor 20 and couples to drive shaft 50. Referring now to FIG. 5,the figure illustrates an electric motor 100 in accordance with oneembodiment of the present invention. In the embodiment shown, transitioncoupling 40 is shown as integral to the hollow rotor 20. In theembodiment shown, the motor 100 is configured to power drive shaft 50 ofa pump section (not shown) which acts upon and moves a working fluidaxially along drive shaft 50, as indicated by direction arrows 70. Theworking fluid enters flow channel 35 via intake ports 60. In theembodiment shown, the first end portion 24 of the hollow rotor 20defines one or more intake ports 60 and the transition coupling 40 lacksintake ports.

Referring now to FIG. 6, the figure illustrates a transition coupling 40which is integral to and forms part of a hollow rotor 20 according tosome embodiments of the present invention. As indicated in FIG. 5, insome embodiments, the transition coupling 40 includes a first coupling41 for joining the hollow rotor 20 with the drive shaft 50 of a pump(not shown) configured to pump a fluid into and through the flow channel35.

In some embodiments, the transition coupling 40 is separate from thehollow rotor 20 and the drive shaft 50, and couples to each, forexample, by friction joints, shrink fittings, threading, bolting,splines, or a combination thereof. Referring now to FIG. 7, the figureillustrates an electric motor 100 in accordance with one embodiment ofthe present invention. In the embodiment shown, transition coupling 40is shown as separate from the hollow rotor 20 and the drive shaft 50. Inthe embodiment shown, the transition coupling 40 defines one or moreintake ports 60 and the first end portion 24 lacks intake ports.

Referring now to FIG. 8, the figure illustrates a transition coupling 40according to some embodiments of the invention. In the embodiment shown,the transition coupling 40 is a single independent component configuredto be joined via a first coupling 41 to a drive shaft 50 and configuredto be joined via a second coupling 42 to a hollow rotor 20. Asindicated, in some embodiments, the transition coupling 40 defines oneor more intake ports 60.

In some embodiments, the electric machine 100 further includes a gapseparating an outer surface of the stator and an inner surface of thehollow rotor. Referring now to FIG. 1, the figure illustrates anelectric machine 100 in accordance with some embodiments of theinvention. As indicated in FIG. 1, the electric machine 100 includes agap 23 (sometimes referred to as air gap) separating an outer surface 31of the stator 30 and an inner surface 21 of the hollow rotor 20.

Referring now to FIG. 9, the figure illustrates an electric machine 100configuration such that a gap 23 between the stator 30 and the hollowrotor 20 is in fluid communication with one or both of the fluid inlet27 and the flow channel 35. In such embodiments, during operation, thegap 23 may further include a portion of the working fluid such that theworking fluid provides for cooling of one or more machine components. Insome embodiments, as described in detail later, the working fluidincludes water and during operation of the machine 100, the gap 23 mayinclude a portion of the pumped water that functions as a coolant fluid.

In some embodiments, the working fluid is transported directly into theflow channel of the stator and in close proximity to the primary heatssources, such as, for examples, winding coils and stator backiron.Without being bound by any theory, it is believed that the machineconfigurations in accordance with some embodiments of the inventionadvantageously provides for improved thermal management.

In some embodiments, as indicated in FIG. 9, the electric machine 100further includes one or more electrical protection devices 34, such as,for example, canning devices or cans. In some embodiments, the one ormore cans 34 are configured to provide a fluid bather so that wellborefluids may be precluded from contacting one or more electricalcomponents of the stator 30. In some embodiments, the electric machinefurther includes one or more fluid bearings, such as, for example, waterbearings 36.

Referring now to FIG. 10, the figure illustrates an electric machine 100configuration such that the gap 23 includes a dielectric fluid or a gas25. In some embodiments, the dielectric fluid or gas functions as acoolant fluid. In some other embodiments, a fluid filled gap separatesan inner surface of the hollow rotor from the stator. In one embodiment,the gas within the gap may be air. In another embodiment, the gas withinthe gap may be a relatively inert gas such as helium or argon. In oneembodiment, the gas within the gap is nitrogen.

In some embodiments, a dielectric fluid filled gap separates an innersurface of the hollow rotor from the stator. In some embodiments, thegap includes a pressurized dielectric fluid. In some embodiments, themachine is filled with a pressurized dielectric fluid which is at ahigher pressure than the environment outside of the machine. In someembodiments the pressurized dielectric fluid leaks outwardly from themachine interior as a means of preventing ingress of the working fluidinto the interior of the machine.

Suitable insulation materials and dielectric coolant fluids include forexample, insulation materials disclosed in U.S. patent applications Ser.Nos. 12/968437 and 13/093306, which are incorporated by reference hereinin their entirety so long as not contradictory to the teachingsdisclosed herein. Non limiting examples of dielectric coolant fluidsinclude silicone oils, aromatic hydrocarbons such as biphenyl,diphenylether, fluorinated polyethers, silicate ester fluids,perfluorocarbons, alkanes, and polyalphaolefins. In some embodiments, acombination of thermal management (using circulating dielectric oil), aswell as the use of inorganic solid motor insulation materials, may allowfor a peak motor temperature of 370° C. In some embodiments, electricmotor configurations in accordance with some embodiments of theinvention, may allow for a peak motor temperature of 330° C.

In some embodiments, as indicated in FIG. 10, the electric machine 100further includes one or more seals 37 configured to preclude fluidcommunication between the gap 23 and one or both of the fluid inlet 27and the flow channel 35. In some embodiments, seals 37 prevent theworking fluid from entering the machine and coming into contact withinternal machine components such as the stator. In some embodiments, theelectric machine 100 further includes one or more fluid bearings, suchas, for example, oil bearings 38.

As indicated in FIGS. 9 and 10, in some embodiments, the electricmachine 100 includes a plurality of modules 101. In some embodiments,the plurality of modules 101 include a hollow rotor 20 and a stator 30disposed within the hollow rotor, wherein the stator 30 defines a flowchannel 35, as indicated in FIGS. 9 and 10. The electric machine 100 mayfurther include one or more cable conduits 80, in some embodiments. Thecable conduits may define a channel for electric cable 85, in someembodiments.

In some embodiments, as described in detail later, the electric machine100 (such as, for example, an electric motor) may be further disposedwithin a well bore. Referring again to FIGS. 9 and 10, in someembodiments, the electric motor 100 may be configured to be disposedwithin a well bore 90. In some embodiments, the electric machine 100 maybe configured to be supported within the wellbore 90 using a pluralityof suitable bearings 92. Further, in some embodiments, as illustrated inFIGS. 9 and 10, the outer surface of the electric motor 100 and an innersurface of the well bore 90 may define a gap 93 that may allow forpassage of a portion of the working fluid (indicated by direction arrows73). In some embodiments, the passage of a portion of the working fluidin the gap 93 between the electric motor 100 and the bore hole 90 mayprovide for cooling of the electric motor 100.

The electric motor configurations in accordance with some embodiments ofthe invention may be useful for a wide variety of applications. Forexample, in some embodiments, the motors provided by the presentinvention may be used in situations in which, during operation, themotor is disposed within a confined space such as a pipe, a shipboardcompartment or a well bore.

In some embodiments, the motor configurations of the present inventionmay be useful in an in-line pump capable of moving a fluid at relativelyhigh rates as compared to conventional in-line pumps. The motorsconfigurations in accordance with some embodiments of the invention andthe pumping systems including them may be useful in a wide variety ofapplications, such as in-line pumps in high flow rate on-boardfire-fighting systems, compact high flow rate shipboard emergency waterremoval systems, in-line high flow fluid transfer pumps in chemicalmanufacture and distribution, in-line high flow fluid transfer pumps inpetroleum refining and distribution, and in line high flow fluidtransfer pumps which can be maintained in an aseptic environment neededin medical and food applications.

In some embodiments, an electric fluid pump is presented. The electricfluid pump, in some embodiments, includes an electric motor including ahollow rotor; and a stator disposed within the hollow rotor, the statordefining a flow channel. The hollow rotor includes a first end portiondefining a fluid inlet, a second end portion defining a fluid outlet;the fluid inlet, the fluid outlet, and the flow channel of the statorbeing configured to allow passage of a fluid from the fluid inlet to thefluid outlet via the flow channel; and wherein the hollow rotor ischaracterized by a largest cross-sectional area occupied by the hollowrotor, and wherein the flow channel is characterized by a smallestcross-sectional area of the flow channel, wherein the smallestcross-sectional area of the flow channel is at least about 25% of thelargest cross-sectional area of the hollow rotor. In some embodiments,the electric fluid pump further includes a transition couplingconfigured to join the hollow rotor to a drive shaft of a pumping deviceto be powered by the motor; and one or more intake ports defined by thetransition coupling, the first end portion, or both the transitioncoupling and the first end portion, said intake ports being in fluidcommunication with the fluid inlet and the flow channel of the stator.In some embodiments, the electric fluid pump further includes a pumpingdevice including one or more impellers fixed to a drive shaft powered bythe electric motor.

In some embodiments, the electric fluid pump in accordance with someembodiments of the invention includes a first set of impellers mountedon a first drive shaft, and a second set of impellers mounted on asecond driveshaft (not shown), said first and second drive shafts beingconfigured to be driven by the hollow rotor, said first and second driveshafts being configured to rotate in opposite directions.

In some embodiments, the electric fluid pump in accordance with someembodiments of the invention includes a pumping device housing (alsoreferred to as a pump housing) defining a fluid inlet and containing apump section including one or more impellers fixed to a drive shaftpowered by the electric motor. In one or more embodiments, the electricfluid pump includes stationary diffusers mounted to an inner surface ofthe pumping device housing.

Referring now to FIG. 11, the figure illustrates an electric fluid pump300 in accordance with some embodiments of the invention. The electricfluid pump includes an electric motor 100 configured to power a pumpsection 200. In the embodiment shown, only a portion of motor 100 isvisible. Pump 200 include a pump housing 210 and impellers 257 attachedto drive shaft 50 which is coupled to hollow rotor 20 of large diameterelectric motor 100 via transition coupling 40. In the embodiment shown,transition coupling 40 is an independent component (i.e. not integral toeither of drive shaft 50 or hollow rotor 20) joining to both drive shaft50 and hollow rotor 20. Pump 200 also includes stationary diffusers 253and thrust bearings 252, in some embodiments. Thrust bearings 252, attimes herein referred to as thrust washers, are positioned between thestationary diffusers and the rotatory impellers, in some embodiments. Insome embodiments, a working fluid may be impelled by a series ofimpellers 257 axially (indicated by direction arrows 70) along driveshaft 50 toward and though intake ports 60.

In the embodiment shown, drive shaft 50 is shown as supported by radialbearing 251. Although only a single radial support bearing is featuredin FIG. 6, a plurality of radial bearings may be included. In someembodiments, the electric fluid pump 300 provided by the presentinvention may further include a high pressure, high temperaturedielectric fluid flow loop that provides for cooling for the motorcomponents (not shown).

In some embodiments, the electric fluid pump 300 is configured tooperate in a borehole. In some embodiments, the electric fluid pump 300is configured to operate in a geothermal production well. In someembodiments, the electric fluid pump 300 may be capable of pumpingproduction fluids from a wellbore or an oilfield. The production fluidsmay include hydrocarbons (oil) and water, for example.

Referring now to FIG. 12, the figure illustrates a geothermal well andthermal energy extraction system 1200 according to some embodiments ofthe present invention. In the embodiment shown, an electric fluid pump300 in accordance with some embodiments of the present invention isdisposed within a geothermal production well 1220. As noted earlier, theelectric fluid pump includes the electric motor 100 and the pump section200. In some embodiments, as indicated in FIG. 12, hot water 1230 from ageothermal field 1205 enters the geothermal production well 1220 and isimpelled to the surface by electric fluid pump 300 powered by electriccable 1225.

In some embodiments, at the surface, energy 1240 may be extracted fromthe hot water in an energy recovery unit 1210 coupled to production well1220 at wellhead 1215. As will be appreciated by those of ordinary skillin the art, various methods may be employed to extract energy, includingsteam generation and driving an electric turbine. In one embodiment, theenergy recovery unit 1210 includes an organic Rankine cycle. In somefurther embodiments, cooled water 1235 produced by removing energy fromthe hot water 1230 may be returned to the geothermal field 1205 viainjection well 1250 where it may absorb heat from the field to producehot water 1230.

As noted earlier, in some embodiments, the electric fluid pump is anElectric Submersible Pump (ESP) optimized for operation within a wellbore and includes at least one outside rotor electric motor inaccordance with some embodiments of the present invention.

In some embodiments of the present invention, the ESP includes one ormore electric motors configured to power one or more pumping sections.In some embodiments, the ESP provided by the present invention includesa modular motor that has been optimized for power density and is dividedinto 16 sections, with a total motor length of approximately 20 meters.In some embodiments, the ESP provided by the present invention includesapproximately 126 impeller/diffuser stages having a total length ofabout 20 meters and a hollow rotor electric motor sections having alength of about 16 meters, making the combined total length of the ESPmotor and pumping sections approximately 46 meters. The total length ofan ESP, according to some embodiments of the present invention, may betypically somewhat longer than the sum of the lengths of the motor andpumping sections due to the presence of additional structural featuresarrayed along the ESP pump-motor axis, for example a protector section.The total length of an ESP, according to some embodiments of the presentinvention, may vary widely, but in geothermal production wellapplications, the length of such an ESP may typically fall in a rangebetween 30 and 60 meters.

In one embodiment, the ESP is optimized for operation within ageothermal well bore having a bore diameter of about 10.625 inches. Inone such embodiment, the ESP is configured to utilize approximately 5.0MW of power, the amount needed to boost 80 kg/second (kg/s) of a 300° C.working fluid (water, with a gas fraction of 2% or less) at a pressureof 300 bar. In such an embodiment, the ESP may be operated to advantageat a pump/motor speed of about 3150 RPM in order to balance systemefficiency and pump stage pressure rise with motor thermal concerns. Adesign-of-experiments analysis using Computational Fluid Dynamics (CFD)carried out by the inventors revealed that pump efficiency as high as78% could be achieved at a flow rate of 80 kg/second through an ESP,according to one or more embodiments of the present invention.

In some embodiments, an electric power generation device is presented.In some embodiments, the electric power generation device includes agenerator including a magnetic hollow rotor; and a stator disposedwithin the hollow rotor, the stator defining a flow channel. Themagnetic hollow rotor includes a first end portion defining a fluidinlet, a second end portion defining a fluid outlet; the fluid inlet,the fluid outlet, and the flow channel of the stator being configured toallow passage of a fluid from the fluid inlet to the fluid outlet viathe flow channel; and wherein the magnetic hollow rotor is characterizedby a largest cross-sectional area of hollow rotor, and wherein the flowchannel is characterized by a smallest cross-sectional area of the flowchannel, wherein the smallest cross-sectional area of the flow channelis at least about 25% of the largest cross-sectional area of themagnetic hollow rotor.

In some embodiments, the electric power generation device furtherincludes a transition coupling configured to join the magnetic hollowrotor to a drive shaft of a turbine device configured to drive thehollow magnetic hollow rotor; and one or more outlet ports defined bythe transition coupling, the second end portion, or both the transitioncoupling and the second end portion; said outlet ports being in fluidcommunication with the flow channel of the stator. In some embodiments,the electric power generation device further includes a turbine deviceincluding one or more impellers fixed to the drive shaft. In somefurther embodiments, the turbine device includes a turbine devicehousing defining one or more fluid inlets.

Referring now to FIG. 13, the figure illustrates a system 2000 forelectric power generation according to one or more embodiments of thepresent invention. In the embodiment shown, the system includes agenerator 900 including a generator housing 910, a hollow magnetic rotor920 configured to rotate within the housing, and a stator 930 containedwithin the hollow rotor 920. The hollow magnetic rotor has a first endportion 924 defining a fluid inlet 927, and a second end portion 926defining a fluid outlet 929. The fluid inlet, the flow channel and thefluid outlet are in fluid communication such that a fluid entering theflow channel 935 via the fluid inlet 927 may pass through flow channel935 and exit the hollow magnetic rotor via fluid outlet 929. In someembodiments, the hollow rotor 920 is characterized by a largestcross-sectional area. The stator 930 defines a flow channel 935 runningthe length of the hollow rotor and being characterized by a smallestcross-sectional area, the smallest cross-sectional area of the flowchannel 935 being at least 25% of the largest cross-sectional area ofthe hollow rotor 920.

In some embodiments, the electric power generation device 2000 furtherincludes a transition section 940 configured to join the hollow magneticrotor 920 to a drive shaft 950 of a turbine device 1000 configured todrive the hollow magnetic rotor 920. In the embodiment shown, transitionsection 940 is shown as defining outlet ports 960 configured to allowpassage of fluid from the flow channel and fluid outlet of the hollowmagnetic rotor. Transition section 940 is coupled to a drive shaft 950of turbine 1000 (at times herein referred to as a turbine device). Inthe embodiment shown, turbine 1000 comprises turbine blades 957 andturbine housing 1010. In some embodiments, the turbine device housing1010 defines one or more fluid inlets.

In some embodiments, during operation, the system for electric powergeneration illustrated in FIG. 13 may generate electricity as follows. Afluid flowing under pressure enters the motor 900 via fluid inlet 927and flows through flow channel 935 as indicated by direction arrows 970.Fluid passes into the transition coupling 940 and exits into the cavitydefined by generator housing 910 and turbine housing 1010. The fluidflowing under pressure encounters the turbine blades 957 during itspassage through the turbine. Energy from the fluid is transferred to theturbine blades causing the blades and drive shaft 950 to rotate. Therotation of drive shaft 950, in turn, causes the hollow magnetic rotor920 to rotate in close proximity to stator 930 and generating electricpower thereby. The fluid, having transferred a portion of its containedenergy to the turbine then passes out of turbine 1000 via turbine fluidoutlet 1027.

Those of ordinary skill in the art will appreciate the closerelationship between one or more embodiments of the electric powergeneration device presented by the present invention and one or moreembodiments of the electric fluid pump presented by the presentinvention. Thus, simply reversing the direction of fluid flow andelectric current flow may convert a power consuming electric fluid pumpinto an electric power generating machine.

The appended claims are intended to claim the invention as broadly as ithas been conceived and the examples herein presented are illustrative ofselected embodiments from a manifold of all possible embodiments.Accordingly, it is the Applicants' intention that the appended claimsare not to be limited by the choice of examples utilized to illustratefeatures of the present invention. As used in the claims, the word“comprises” and its grammatical variants logically also subtend andinclude phrases of varying and differing extent such as for example, butnot limited thereto, “consisting essentially of” and “consisting of.”Where necessary, ranges have been supplied; those ranges are inclusiveof all sub-ranges there between. It is to be expected that variations inthese ranges will suggest themselves to a practitioner having ordinaryskill in the art and where not already dedicated to the public, thosevariations should where possible be construed to be covered by theappended claims. It is also anticipated that advances in science andtechnology will make equivalents and substitutions possible that are notnow contemplated by reason of the imprecision of language and thesevariations should also be construed where possible to be covered by theappended claims.

The invention claimed is:
 1. An electric fluid pump, comprising: (i) anelectric motor comprising: (a) a hollow rotor; and (b) a stator having acavity, and disposed within the hollow rotor, wherein the cavity in thestator defines a flow channel; wherein the hollow rotor comprises afirst end portion defining a fluid inlet, a second end portion defininga fluid outlet; the fluid inlet, the fluid outlet, and the flow channelof the stator being configured to allow passage of a fluid from thefluid inlet to the fluid outlet via the flow channel; and wherein thehollow rotor is characterized by a largest cross-sectional area ofhollow rotor, and wherein the flow channel is characterized by asmallest cross-sectional area of the flow channel, wherein the smallestcross-sectional area of the flow channel is at least about 25% of thelargest cross-sectional area of the hollow rotor; (ii) a transitioncoupling configured to join the hollow rotor to a drive shaft of apumping device to be powered by the motor; (iii) one or more intakeports defined by the transition coupling, the first end portion, or boththe transition coupling and the first end portion; said intake portsbeing in fluid communication with the fluid inlet and the flow channelof the stator; and (iv) a pumping device comprising one or moreimpellers fixed to a drive shaft powered by the electric motor.
 2. Theelectric fluid pump according to claim 1, comprising a first set ofimpellers mounted on a first drive shaft, and a second set of impellersmounted on a second driveshaft, said first and second drive shafts beingconfigured to be driven by the electric motor, said first and seconddrive shafts being configured to rotate in opposite directions.
 3. Theelectric fluid pump according to claim 1, further comprising stationarydiffusers mounted to an inner surface of a pumping device housing. 4.The electric fluid pump according to claim 1, wherein the electric fluidpump further comprises a motor housing, wherein the hollow rotor isdisposed within the motor housing and configured to rotate within.